1. Field of the Invention
The present invention provides a pointing device and, in particular, a pointing stick with a rectangular-shaped hollow structure.
2. Description of the Prior Art
Pointing devices are used to control the movement of a cursor on a computer monitor. They are widely used in all kinds of desktop and laptop computer peripherals, such as keyboards, mice, joysticks and remote controls.
Please refer to FIG. 1, which is a schematic view of a conventional pointing stick device 10. The pointing stick device 10 comprises a substrate 11, a monolithic cylindrical stick 12 positioned on the substrate 11 to control the two-dimensional movements of the cursor on a computer monitor, and a plurality of strip strain gauges 14 installed at orthogonal positions around the stick 12 to measure pressure and generate corresponding pointing signals.
Please refer to FIG. 2, which shows schematically the pointing stick device 10 under a force. As shown in FIG. 2, when a horizontal external force is applied on the stick 12, the strain gauges 14 bend and distort along with the stick 12. The distortion of the strain gauges 14 generates the corresponding pointing signals.
However, the conventional pointing stick device 10 generates pointing signals using the strain gauges 14 that measure simply the bending of the stick 12. Therefore, the sensitivity of the strain gauges 14 is limited by the elasticity of the stick 12 and the strains generated due to bending. This makes it difficult to improve the sensitivity of the pointing stick device 10.
Consequently, it is a primary object of the present invention to provide a pointing stick with a rectangular-shaped hollow structure to overcome the above-mentioned defects.
Briefly, the present invention discloses a pointing stick device having a substrate, a rectangular-shaped hollow structure installed on the substrate and having a central axis substantially vertical to the substrate, at least one strain gauge installed on the rectangular-shaped hollow structure, and a claw structure. The claw structure has at least one claw, and is used to impart a pressure onto the rectangular-shaped hollow structure and curve the rectangular-shaped hollow structure. When the claw of the claw structure imparts pressure on the rectangular-shaped hollow structure, the strain gauge distorts, following the curve of the rectangular-shaped hollow structure, to produce corresponding pointing signals.
It is an advantage of the present invention that the claw structure disposed on the rectangular-shaped hollow structure is better able to distort the rectangular-shaped hollow structure. This improved distortion leads to greater deformation of the strain gauges, and thus improves the overall sensitivity of the pointing stick device.
These and other objectives of the present invention will no doubt become clear to one skilled in the art after reading the detailed description of the preferred embodiment, which is illustrated in the following figures.